Primary care settings offer an excellent opportunity to identify and address unhealthy substance use ranging from at-risk use to substance use disorders (SUD). Practitioners can help with problem identification, brief counseling, follow-up/monitoring, motivating patients, and linkage to specialty care. However, opportunities are often missed. Even when SUD are identified, there are low rates of treatment initiation (1 SUD service in any setting within 14 days after diagnosis) and engagement (2 services in 30 days after initiation) as defined in the widely-used HEDIS performance measures. Both patients and providers play a role. For example, providers may lack skills, time or motivation; patients may face stigma, denial or access barriers. The Veterans Health Administration (VA), like other systems, faces a challenge in this area. About 7% of all veterans and up to 25% of younger cohorts have SUD. Many more have at-risk use. Among VA patients identified with SUD in an outpatient medical (non-behavioral health) setting only 9% initiate care, and 31% of those engage in care. Yet these are recognized as important parameters of early-phase care and engagement has been linked to better outcomes. The aims of this exploratory study in a large VA medical center are to: 1) Examine screening patterns and early care trajectories including provider response and service use following a) positive drug or alcohol screening in primary care, and b) SUD diagnosis; identify associated patient and provider factors. 2) Conduct pilot testing of patient incentives to enhance treatment initiation and engagement for primary care patients identified with SUD in primary care. 3) Assess patient and provider perspectives on early-phase care and treatment incentives. The study environment includes electronic health records, SBIRT training, and a brief drug screen added to well-adopted annual alcohol screening. In Aim 1, we analyze screening patterns and early care trajectories. In Aim 2, we pilot test contingency management-based incentives for early treatment participation for primary care patients with SUD (n=120 patients randomly assigned to incentives or control). We examine utilization and substance use outcomes. Prize-based financial incentives feature higher probability for low-value prizes. In Aim 3, we interview patients and providers on screening, early-phase care challenges, and incentives. This innovative study will shed light on early care patterns for patients identified in primary care with unhealthy substance use, making a unique contribution through analysis of linked screening, provider response and utilization data. It will yield preliminary evidence on how patient incentives may enhance treatment participation (untested in primary care). It will tap patient and provider views on early-phase car and incentives. Results will inform efforts to improve care as well as design of full-scale trials (e.g. comparing different levels of incentives). Thus, the study represents a novel line of research with far-reaching potential to improve quality of care.